A secondary battery that is safe and high in reliability under any global environment is demanded for an environmental power generation technology by which electricity generated by small energy such as sun light, vibration and a body temperature of a person or an animal is accumulated and utilized for a sensor or as wireless origination power.
In a liquid secondary battery utilized widely at present, it is concerned that, if the number of cycles of its use increases, then a positive-electrode active material may degrade to decrease the battery capacity or an organic electrolyte in the battery may be ignited by battery short-circuiting arising from formation of dendrite.
Therefore, a secondary battery that uses a liquid electrolyte is poor in reliability and safety where it is tried to use the secondary battery in an environmental power generation device whose utilization, for example, for 10 years or more is expected.
Therefore, attention is paid to an all-solid-state secondary battery in which all constituent materials are solid. The all-solid-state secondary battery has no possibility of liquid leakage, ignition and so forth and is excellent also in a cycle characteristic.
For example, as a solid electrolyte for use with an all-solid-state secondary battery, a solid electrolyte for which an oxide such as LaLiTiO is used is available.